substr within makefile

[Jaitly, Rahul]

Hi,

 

I have a query with regard to writing makefile. I have a string that I pass to my makefile. I need to access each character of that string within my makefile and do processing based on what each is respectively. Is there a substr or equivalent function that I can use to access each character within a string by position of that character. So like accessing nth character of a string->

 

e.g. 3^rd character of $(example) is ‘a’

 

Thanks,   

Rahul